


Christmas Exchange

by The_Lady_of_Purpletown



Series: A Case of Illusion [1]
Category: Harry Potter - J. K. Rowling, Sherlock (TV)
Genre: Christmas, Cuddling & Snuggling, Dragons, First Kiss, Fluff, Hogwarts, Hufflepuff Common Room, Johnlock Gift Exchange, M/M, Potterlock, Sleeping Together, Threats
Language: English
Status: Completed
Published: 2014-12-25
Updated: 2014-12-25
Packaged: 2018-03-03 02:53:11
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,030
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2835395
Author URL: https://archiveofourown.org/users/The_Lady_of_Purpletown/pseuds/The_Lady_of_Purpletown
Summary: <blockquote class="userstuff">
              <p>Sherlock is claiming John's common room again. John finally finds the courage to ask his best friend something that has been on his mind for some time. Could be dangerous...</p>
            </blockquote>





	Christmas Exchange

**Author's Note:**

  * For [endlesshorizons](https://archiveofourown.org/users/endlesshorizons/gifts).



> For [justjohnlockstuff](http://justjohnlockstuff.tumblr.com)'s Johnlock Christmas Exchange.

"I _knew_ it,” Sherlock said, shutting his folder with a snap that startled John enough that he made a blot on his parchment.

“What?” John asked, a little annoyed.

“The dragon smugglers.” Sherlock gave an impatient flick with his wand so the Potions homework in John’s lap looked more pristine than it had done before. “They have their base in Cardiff.”

“Brilliant,” John said, smiling a little at his own writing. “How do you know?”

“Oh, John, they have left traces _everywhere_.”

Both the gleam in Sherlock’s eyes and the fact that the investigation had been started by the Ministry three months earlier told John that that couldn’t be entirely true, but he leaned in closer to see the file Sherlock was holding.

“I can’t believe Mycroft didn’t realise this,” Sherlock continued, shaking his head. “I’d almost think they’ve paid him to shut up...”

“Yes, alright, Sherlock. Tell me what you’ve found out,” John said with a fond eye roll.

“Look.” Sherlock pulled an article out from the stack of newspaper clippings on the floor and tapped it with his wand, at which a tangle of lines appeared. He pointed at the centre of them. “This is where they are operating from. All the ends of the lines are the spots where dragon sightings are reported. Let’s say that half of them were true –“ He tapped the article again and half of the lines vanished, “– then it is still quite obvious.”

John nodded. “So they didn’t even bother to connect the dots?”

“I told you they’re idiots at the Ministry,” Sherlock shrugged. “But there is more.” He discarded the article and picked another one from the stack, seemingly at random.

John stared at it blankly. “Er...”

“Can you believe their arrogance?” In his enthusiasm, Sherlock hopped from his spot on the floor onto the armrest of John’s chair.

Instinctively, John shifted closer to his warmth, but the thin piece of paper didn’t make him any wiser. “It’s just a clipping. And you’ve marked four letters, but... I doubt ‘HAHA’ has to mean anything. So unless you think it’s arrogant that they mucked up the grammar in the fifth sentence...”

“’HAHA’ means _everything_ ,” Sherlock said dramatically, taking another clipping. “Those are the first letters of the first word of every other sentence. Now look at this one.”

He pushed it into John’s hands; once again, it was about the dragon smugglers, and it was dated a few days after the first one. “’THEY’?” John read.

Sherlock nodded. “The writer is giving us a message. A very, very stupid one. Because a week later, she wrote her sentences so that if you knew where to look, you’d read “WILL”. The second sentence starting with an ‘L’ was such a disaster that it caught my attention and that’s why I had a closer look at all the others. Now guess what she did after that... ‘NEVER’, ‘KNOW’, ‘ITWAS’ and, in a very short one saying that the investigation still hasn’t had any results: ‘ME’.”

“You’re kidding,” John said, his eyes wide.

“Nope. But our oh so brilliant reporter, Ms Kitty Riley, must be laughing up her sleeve. Her business is booming, they can’t find any clues and she can even leave secret messages in the Daily Prophet. Let’s see if she’s still laughing when I’ve sent an Owl to Magical Law Enforcement.” He swept his clippings back into the folder, put it aside and gave John an expectant look.

“Amazing,” John said, heart-felt. “They would have been searching for ages without you.”

Sherlock nodded. “Fools.” He let himself slide off the armrest into the chair, where there actually wasn’t room for him, but John shifted to allow it anyway. Not that there weren’t enough chairs for both of them. Apart from a group of whispering third-years in the far corner – probably up to something illegal – the Hufflepuff common room was completely deserted. Most students had gone to bed, and not that many had stayed at Hogwarts for a start. Had Sherlock not been there, John would have spent the loneliest Christmas of his life, unable to face the chaos that called itself his home. He was the only sixth-years from Hufflepuff in the castle. But Sherlock _was_ here. In the wrong common room, as usual, because neither of them found the Slytherin common room very homely – and at the moment more or less in his lap. So it had become a very good Christmas holiday indeed.

And yet, John kept fretting about something. Not constantly, as Sherlock would drag him along throughout the day and John wouldn’t really think at all if he was running after him, thinking up fibs to distract wandering teachers, or training his aim by covering Sherlock in snow (at the one occasion _he_ had managed to drag Sherlock along for a change). But at moments like this, when all was quiet and Sherlock had just done something clever and they had somehow ended up snuggling again... That was when his mind returned to the same question over and over, although he never dared to ask it. It was ridiculous, maybe even wrong, to want this so badly. He had even considered to ask it on Christmas Eve, instead of a gift, but that felt like he was not giving Sherlock a choice – and he would already have bought him something, anyway.

“John?”

John blinked and found that Sherlock was frowning at him. “Yes?”

“You’re thinking very loudly.” Sherlock gave him a searching look.

“Oh. Sorry.” John blinked again. “You didn’t actually hear what I was thinking, did you? I mean, that Legilimency thing Greg was talking about sounded pretty creepy...”

Sherlock rolled his eyes. “I don’t need magic to see that you’re worried about something. It’s probably ridiculous.”

John scowled, meanwhile wondering if Sherlock was right. They usually had no personal boundaries whatsoever. Sherlock _was_ in his lap. Was it ridiculous to think there was any difference from cuddling in a bed? To finally ask him to stay over and share warmth? Maybe Sherlock would just find it practical. Every night he had to walk the cold corridors back to his own common room, only to meet John again at breakfast and spend the rest of the day together. Actually, _that_ was sillier than asking him to stay. Then again, John couldn’t just present the idea as a practicality, or Sherlock would ridicule it, saying that he wasn’t afraid to be caught out at night by the teachers, as they couldn’t possibly expel him with his marks – even though they must be wondering what he wanted to achieve with the set of subjects he had chosen after his OWLs.

On the other hand, John could hardly explain to Sherlock how much it would mean to have him close when he was asleep. If he admitted that... He couldn’t lose Sherlock’s friendship by disgusting him. He simply couldn’t.

And just like that, he was all the way back to the start of his inner conflict.

Sherlock sighed. “You might as well tell me about it.”

“I... Fine,” John heard himself saying, to his own surprise. At some point, he should probably learn not to give in to Sherlock’s every wish, but perhaps now wasn’t the time to start. “I was just wondering. I mean...”

“Do try to finish your sentence before I’ve fallen asleep.” Sherlock snuggled into John’s shoulder, which helped.

“Yes. You’re sleepy. That’s good,” John babbled, before realising he was rather showing his hand there.

Sherlock lifted his head to give him a look.

“There’s no one in my dormitory,” John said quickly, squirming under Sherlock's scrutiny. He decided that putting his now forgotten Potions homework neatly on the table in front of him was a good way to avoid Sherlock’s gaze, even if it was a little awkward to move forward while Sherlock was still leaning on him.

“Of course there’s no one there,” Sherlock said, sounding puzzled. “You are here. Was this supposed to give me some clue?”

“ _Yes_.” Trust Sherlock to exasperate him enough that he _would_ look at him. “I’d like you to stay. But... But you don’t have to. I mean, only if you want to. It’s fine if you don’t. Really.”

“What’s _wrong_ with you tonight?” Sherlock asked, and John cringed. He shouldn’t have asked. It was a mistake and he would regret it for the rest of his life, and really, he should have known, there was a reason why he had hesitated for so long, he should have listened to himself...

“I don’t mind staying here,” Sherlock said with a shrug. “I don’t know why that was so hard to ask. You don’t have any bad sleeping habits or problems that I should know about – except for the occasional nightmare, but I’m sure I can handle that.”

“I’m not talking about you sleeping in one of the other beds,” John said, very quietly and in one breath.

“Don’t be boring.”

“Right. But the beds are small.”

“So is this chair,” Sherlock pointed out, pushing John back in place to reclaim his shoulder-pillow.

“People might talk,” John said quietly.

“People do little else,” Sherlock shrugged. “Besides, it was your idea.”

“Yes. I don’t mind. It’s just that perhaps you didn’t like them thinking...”

“I’m hardly going to discourage them the one time they think at all, John,” Sherlock said, sounding exasperated.

“Oh.” John wondered if that was supposed to make him feel smug. Because it did, a little. “So... Can we move?”

Sherlock groaned, but then sat up and gave John’s shoulder a remorseful look. “I guess it’s better for you if we don’t fall asleep here.”

“Much better,” John nodded, without really thinking of his old Quidditch injury.

As he was being brave tonight, he decided that he could as well hold Sherlock’s hand all the way to the dormitory after Sherlock had pulled him to his feet. One of the third-years let out a high-pitched giggle when they passed them, which John wouldn’t have paid much attention to if her friend hadn’t very loudly whispered: “Quiet, Tessa!”. Blushing, he crossed the room a little faster and then pulled the round door shut behind them.

There, he spent a moment feeling awkward, but that was solved very quickly by Sherlock flopping onto his bed, fully dressed.

John climbed in next to him, seeing no other option than to lie half on top of him to avoid falling out of bed.

“You’re allowed to change into your pyjamas, you know,” Sherlock remarked, raising an eyebrow.

“Boring,” John said, not planning to move ever again now he had finally achieved this.

“Okay.” Sherlock pulled him even closer and nuzzled his hair.

 

...

 

When John was startled awake by a loud shriek, neither he nor Sherlock had moved an inch. Both boys sat up almost at the same time.

“Third-years girls dormitory,” Sherlock mumbled, before jumping off the bed and rushing out the door.

Indeed, as they entered the common room, the group of girls that had been giggling at them was standing huddled together outside another dormitory door.

“What’s going on?” John asked, quickly throwing a hand over his hair so it didn’t look too mussed.

“There’s... there’s a dragon!” one of the girls managed in a shaky voice.

“A dragon? What, here?” John said incredulously. By his side, he felt Sherlock shift towards the door. “Wait, no, Sherlock...”

But of course, the taller boy had already opened the door slightly to peek in, and a horrible roar met them, making the girls scream.

“Merlin’s left testicle,” John mumbled to himself. “How...”

“It doesn’t matter how now, John,” Sherlock said quickly. There was a loud thud against the door and he closed it quickly. “It’s going to break out any time now. John, I need you to distract it. I’ll find help. You three...” He directed himself to the girls. “Get out of here.”

“But...” the shortest girl protested.

“OUT!”

Sherlock ran off, and two of the girls hurried to the common room’s exit. The other seemed to hesitate as she looked at John. “We’ll guard the corridor,” she promised. “Should it get past you... Well...” She bit her lip, shook her head and then quickly followed her friends.

“Right,” John muttered to himself. Firmly holding on to his wand, he listened as the beast behind the wall growled and shifted around, though it seemed to leave the door alone for now. He glanced over his shoulder and hoped that Sherlock would find help soon. A bit of danger was always exciting, but John didn’t quite look forward to facing a live dragon on his own. Then he thought he heard Professor Sprout’s voice in the distance, answered by Sherlock’s deep tones. Relieved, he took a step back – but immediately his attention was caught by a loud ripping noise as the yellow door in front of him shattered into pieces and a giant, green head came through.

“ _Stupefy_!” John cried out immediately, holding out his wand, but the red beam of light simply bounced off the beast’s thick scales. “Sherlock!”

He heard running footsteps, but couldn’t take his eyes off the creature that was now driving him backwards, its silvery claws hitching on the carpet. John thought the dragon had to be quite young, as its head only just scraped the ceiling. Then, suddenly, it launched itself forward, snapping at John’s injured shoulder.

“JOHN!” Sherlock bellowed somewhere behind the dragon, and Professor Sprout was rambling off a whole stream of spells.

Squeezing his eyes shut, John prepared himself for the pain that would break through his body. Any second now, the beast would bite down... And then there was a breeze of wind past his body and the heat the creature had spread was gone.

Cautiously, John dared to open one of his eyes just a little. There was no sign of the dragon. Only the very confused faces of Sherlock and Professor Sprout in front of him.

“Where... where did it go?” John stammered, reaching out a hand to support himself against the wall and almost landing it on a decorative cactus.

“No idea,” Sherlock said, looking very pale.

“I think...” Professor Sprout said, crouching to pick something up from the ground. “I think it’s... this.” She held up a small, square piece of parchment.

“What?” Sherlock said weakly.

The Hufflepuff Head held her wand to the note and then nodded. “There never was a dragon,” she said.

“There never... Professor, didn’t you see it?” John asked, for a moment wondering about her mental health.

“I did,” she nodded. “But it wasn’t real. It was an illusion.”

“It felt real enough to me!” John snapped, trying to keep himself from shouting. “I could bloody feel its heat! It was this close to biting me!” He kept his index and thumb almost against each other.

Sherlock burst forward, ignoring Professor Sprout’s warning “Wait!”, and pulled John against his chest.

“I shouldn’t have left you alone,” he said, his eyes looking wild.

“Well... At least it didn’t leave a jinx with the note,” Professor Sprout said, looking a little disapproving at the fact that Sherlock had crossed the distance between him and John without thinking.

“What does it say?” John asked, gently pushing Sherlock off a little so he could at least look at his Head of House – although he gladly accepted that the Slytherin kept an arm around his waist.

“I think it’s directed at you two,” Professor Sprout said, handing it to John.

He looked down at it and read:

‘ _Dearest boys,_

_Well done! You must be sooo proud. Have a little in-theme treat after all that brainwork._

_I’ll be in touch soon!_

_JM_ ’

“Do you know anyone with those initials, who would be in for this kind of prank?” Professor Sprout asked sternly, looking from John to Sherlock.

Both of them shook their heads.

“It... It was some very advanced spell work,” Sherlock said, not quite sounding like himself and tightening his arm a little around John. “To make the dragon so real that we could feel it... And to show it in three dimensions without any transparent bits... Showing up only at the moment someone looked in... I don’t think I could have done it.”

“You don’t think it was a student, then?” John understood what he was saying.

Professor Sprout nodded slowly. “You may have a point. We will look into this. It is worrying that someone outside the castle could smuggle a piece of magic like that into a school dormitory. Even if it turns out to be harmless.”

Sherlock frowned.

“But why put it in the girls’ dormitory if they wanted _us_ to see it?” John wondered out loud.

“Dramatic effect,” Sherlock mumbled. “It was a threat.”

Professor Sprout held out her hand. “I will take the note to the Headmaster and report what has happened. He can study the spell that was attached and perhaps find some clues to the person who was responsible. It’s best if you two go back to bed now. I’ll tell Miss Quin, Miss Jones and Miss Gillyweed that they can use another dormitory tonight.”

John nodded. “Thank you.”

Sherlock took one last look at the piece of parchment before placing it in her hand.

“By the way...” she said as she took it. “Mr Holmes... Why weren’t you with your own House? I know you spend most days here, but...”

“Sleepover,” John said quickly. “It was a tradition at home that I could have a friend over some time during the Christmas holidays. You know, before... everything. And I... missed it.”

“I see.” Professor Sprout’s expression softened and John almost felt guilty about using her knowledge of his home situation in a blatant lie.

“Well... Goodnight, Mr Watson, Mr Holmes. I will inform you of Professor Dumbledore’s findings in the morning.”

“Thanks,” John said. “Goodnight, Professor.”

He looked up at Sherlock, who was looking paler than usual, his eyes set on a point far away. “Sherlock, are you okay?”

Sherlock sharply looked down at him. “You almost weren’t,” he said hoarsely.

“It was just an illusion. It’s fine,” John said.

Sherlock shook his head. “It would have been my fault.”

John put his arm around Sherlock’s waist too and squeezed him a little. “It wouldn’t have helped us if you had stayed with me to be eaten by a dragon, certainly if it had been a real one. Getting help as soon as possible really was the best option. And we’re fine.”

Sherlock took a deep breath and then nodded slowly. “I don’t understand how they knew I had solved the case.”

“What case?” John asked.

“The dragon smuggling, of course. I haven’t even had the chance to inform the Ministry. And there was almost no one around tonight.”

John thought for a moment as he gave Sherlock a gentle push, trying to steer him back to his dormitory. “Maybe you should talk to Dumbledore before you write about it. In case this really was a threat.”

“Oh, I have no doubt it was,” Sherlock said. “But I’ll send that Owl anyway. Even if they want to stop us, it’ll be better if they don’t have the smuggling circuit ready to send us a _real_ dragon, right? And it might provoke them to lay out new clues... JM...”

John smiled a little as he closed his dormitory door. “You’re not going to sleep, are you? With a nice new riddle like that on your mind?”

“Oh...” For a moment, John could see something like a small glimpse of panic in Sherlock’s eyes. “No, I think I can try. Better to get to work on it tomorrow when I’m rested.” He took a step towards the bed, but then stopped. “Actually... There is one thing that I should check. Can you take off your shirt for me?”

John stared and willed himself not to blush. “What?”

“Your shirt.” Sherlock rolled his eyes. “I need to see your shoulder. The dragon’s teeth would have pierced you, right? What if the spell left something behind? Some kind of tracker, something to listen in on our conversations, to make it even easier to know how far we are in our investigation... Whoever planted that illusion in the girls’ dormitory doesn’t really need something like that, it seems, but it won’t hurt to check anyway.”

“Oh. Of course.” John quickly pulled his shirt over his head and turned his left shoulder towards Sherlock, who made a scanning motion over it with his wand.

“Looks okay,” Sherlock said, repeating the movement with his fingertips. He stopped at the start of John’s upper arm and left his hand there, gazing down at him.

“You never actually had any sleepovers at home, did you?”

“No,” John said, with a wry chuckle at the thought. “Of course not.”

“I’m happy that you asked me to stay.”

John studied Sherlock’s face, slightly surprised at the remark. “Yeah. Me too.”

“I probably never even wished you a merry Christmas properly,” Sherlock said, frowning as if trying to remember.

“No, probably not,” John smiled. “But that’s fine. You didn’t have to.”

Sherlock shook his head, and before John knew it, he was suddenly very, very close. Close enough to brush his lips softly against John’s. Which, making John’s heart skip several beats, he actually did.

“Will that do?” Sherlock whispered, as he stood upright again and blinked as if he couldn’t really believe what he had just done himself.

“I... Yes,” John said breathlessly. “I think that expresses the sentiment quite well.”

“Good.” Sherlock grinned and flopped back onto the bed.

For a few seconds, John was still staring at him, before a chuckle escaped him and he quickly put on his pyjama top before joining Sherlock.

“You really have no idea who that JM person is?” he asked, resting his head on Sherlock’s shoulder.

“No,” Sherlock smiled, stroking John’s back and looking very happy. “Just that they’re something new.”

John hummed and nuzzled his neck, deciding that he didn’t mind it at all if Sherlock would be thinking about it all night, as long as he wouldn’t move out of his arms.

“I’m an idiot, though,” Sherlock said after a moment.

“Huh?”

“Riley might have nothing to do with it. If they know exactly how far we got, then it would be very strange indeed if that reporter was anything more than a messenger. Someone who goes to the length of creating that illusion wouldn’t make it so easy to find out their identity. But we wouldn’t have known that if they hadn’t sent us the dragon. So for some reason, they must want me to realise I was wrong.”

"Oh,” John said. “Do you think they’ll gain something from framing Ms Riley?"

“They’re not necessarily framing her. She might have _some_ role in it. I just seriously doubt she’s leading any of their operations.” Sherlock absent-mindedly kissed John’s hair, as though they had been lying like this many times before and it simply was what he did.

John blushed at the thought that maybe Sherlock had simply been imagining it as many times as he had.

“You’ll sleep here for the rest of the holidays, right?” he asked.

“Of course,” Sherlock said. “And perhaps after that. I could make a deal with that annoying guy, what’s his name, Anderson. Surely he’ll want to leave your dormitory if it earns him a bed next to Wilkes’.”

John chuckled. “I doubt the teachers are going to let you two switch Houses.”

“Don’t be ridiculous. Have you seen Sprout? She’d give us our own flat if she could.”

“I do feel a bit guilty about lying to her,” John said.

“No need. I think you handled that quite well. And she’s got other things on her mind right now,” Sherlock shrugged.

“As do you.” John smiled and pulled the patchwork quilt over both of them.

“Yes. But you get some sleep, John. I promise I’ll wake you up if I get a particularly brilliant idea.”

John chuckled. “I don’t doubt you will. Goodnight and… merry Christmas, Sherlock.” He pressed another quick kiss to the Slytherin’s lips.

Sherlock beamed at him. “Merry Christmas.”

**Author's Note:**

> As this story came to life, quite a few possibilities for a further plot crossed my mind. I may continue it if I find the time. But for now: happy holidays!
> 
> Edit 26 January 2016: While this story can still be read on its own as a oneshot, I have finally found the time and inspiration to continue it in the next part of the _A Case of Illusion_ series. This will be a (much) longer story, so if you prefer to stop reading here, that’s fine. It is in fact the reason why I didn’t simply add the next chapters in this same story: readers had advised me to make it into a series because some people prefer to read completed stories and it’s been a long time since this first chapter was published. But of course I invite you to discover the rest of my Potterlock. Enjoy reading and don’t forget to drop me a comment now and then :)


End file.
